Two-cycle motor.



J. D'HARVENG.

TWO CYCLE MOTOR.

APPLICATION FILED APR. 2, 1912.

Patented Nov. 9, 1915.

2 SHEETS-SHEET I- coLuMBM PM NOURAPM co.. WASHINGTON, n.1:`

J. DHARVENG.

TWO CYCLE MOTOR.

APPLICATION FILED APR.2. 1912.

Patented Nov. 9, 1915.l

2 SHEETS-SHEET 2.

COLUMBIA PLANOGRAPH COWA5H|NGTDN. D. c.

JULES DHARVENG, 0F LIEGE, BELGIUM.

TWO-CYCLE MOTOR.

Specification of Letters Patent.

Patented Nov. 9., i915.

Original application filed April 1, 1911, Serial No. 618,415. Divided and this application filed April 2, 1912.

Serial No.

To all whom 'it may concern Be it known that I, .IULn-s DHnnvn-No, a citizen of Belgium, and resident of Liege, in the Kingdom of Belgium, have invented certain new and useful Improvements in Two- Cycle Motors, being a division ot my application Serial No. 618,415, filed April 1, 1911; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked therein, which form a part of this specilication. l

The present invention relates to chargereservoirs for 'the combustion mixture and scavenging air of two-stroke cycle engines, and is especially adapted tor engines oi high speed.

As the supply of the gas-air mixture or the necessary quantity of scavenging air for two-str0ke cycle motors must take place during a very small interval of time of the piston travel, the ditliculty of supplying proper quantities of mixture or air, increases with the speed of such engines. This difliculty does not arise in four stroke cycle engines, as the admission period can, if desired, extend over an entire stroke of the piston. Heretofore the charging of two stroke cycle motors at high speeds has been eilected by- 1. Increasing the charging pressure in the charge reservoirs or chambers and-2. By increasing the size of the admission oriiices to the cylinder. Both means reduce the eiliciency of such motors, and have been unavailable to increase the speed beyond 1200 revolutions per minute.

The present invention provides means for facilitating the admission, and overcomes the disadvantages above set forth.

Engines constructed according to my invention have attained an unexpected and remarkably high speed of 2500 revolutions per minute.

Experience shows that in the best known engines having charge chambers, the short time that the inlet ports can remain open causes a decrease of pressure in said chambers only for a comparatively short distance from the ports. This shows that none of the charge beyond said distance has entered the cylinder, and only that portion of the charge adjacent the ports has been able to enter the cylinder.

According to my invention, it is possible to introduce a full charge during the momentary opening of the ports, because the charge, as a whole, is contained in a chamber entirely surrounding the cylinder and the particles of the charge are maintained as closely as possible around the ports.

The section at right angles to the cylinder axis through the chamber must be annular, as small as possible, and not of undue circumferential extent consistent with practical construction; the chamber must discharge directly through the ports; must contain a full charge, and not be connected thereto by pipes' or other connections, as such construction will not permit proper admission, as above sct forth.

It should be noted also that the form of reservoir in accordance with this invention. is adapted to the case in which the reservoir is subdivided into two parts by a horizontal partition in such a manner that it contains the scavenging air and the mixture separately.

Figure l shows the application of the invention to a single cylinder motor, the reservoir being divided into two. Fig. 2 shows the application of the invention to a motor the two 'cylinders of which are relatively distant. Fig. 3 is a horizontal section on the line lfb-B in Fig. 2. Fig. 4 shows the application of the invention to a motor the two cylinders of which are relatively close together. Fig. 5 is a section on the line C--D in Fig. 4.

In the case illustrated in Fig. 1 a cylindrical slide or sheath 2 is lixed to the driving piston 1; at its upper part this sleeve .slides in a chamber 5 between the part 3 ot the cylinder and the cylinder head 4. The sparking plug 6 is arranged in the cylinder head 4.

Around its periphery the sleeve 2 is perforated with two series of orifices 7 and 8. The oriiices S are arranged in immediate proximity to the bottom of the piston. The orifices 7 are arranged in proximity to the cylinder head 4 when the piston is at its dead point at the end ot' the expansion. One of these series of orifices serves for the admission and the other for the exhaust. In the case represented in Fig. l it is the orifices 7 that coincide with the exhaust ori- Y fices 9 and the piston is represented at its the charging pump whose piston in the case represented is constituted by the lower part of the driving piston 1. The air drawn through the valve 14 into the pump- 15 is forced through the valve 16 into the reservoir 12 and through the valve 17 into the reservoir 13. The fuel is introduced into the lower reservoir 12 through the jet or jets 18. The motor operatesvas follows: The piston being at the top of its stroke the various orifices are closed and a mixture of air and fuel is compressed between the said piston and the cylinder head, this mixture being ignited by the sparking plug G, the piston makes its driving stroke and the said mixture expands until the moment at which the orifices 7 uncover the exhaust ports 9. Slightly afterward the lower edges of the orifices 8 uncover the orifices 11 of the reservoir 18 containing pure air under pressure. This air rushes into the cylinder and effects the scavenging; an instant later the lower edge of the orifices 8 uncovers the orifices 10 of the reservoir 12, the air contained in this reservoir 12 and intended to form the combustible mixture with the fuel, enters the cylinder with the fuel supplied through the jet or jets. The piston then ascends closing all the orifices previously opened and co1n presses the explosive mixture.

TWhen, as represented in Figs. 2 to 5, there is no horizontal partition separating the scavenging air from the mixture air the fuel cannot be introduced from the moment of opening the orifices but only after the quan tity of scavenging air which is alsov contained in the single reservoir has been introduced into the cylinder. It is known that this arrangement can be realized b'y'the employment of the device forming the object of my application No. 618415 of the 1st April 1911.

Figs. 2 and 3 relate to a motor with two cylinders relatively distant in such a manner that the charge reservoir 19 of each cyl# inder may present the ideal annular form. In the case illustrated in Figs. 1 and 5V on the contrary the cylinders are relatively close together. In this case the two reservoirs constructed as before would meet as shown in broken lines g (see Fig. 5). If a partition 2O were merely provided between the points of intersection X and g (Fig. 5) the capacity of the reservoirs would be reduced. InY order to avoid this the capacities indicated by the vertical dotted lines are added to each reservoir. These capacities added to the ideal annular volume are selected in such a manner that they are as close as possible to the orices 8 and 8 in front of which the cross section and directly communicating with the cylinder through said ports and of sufiicient capacities to contain the requisite quantities of fiuid for each charge before ad'- mission thereof into the cylinder', a pump piston on the end of the engine piston, a

pump cylinder therefor communicating with both of said chambers,l and nonreturn valves to prevent the air compressed into said chambers from returning to the pump cylinder. c Y Y In testimony whereof I aflix my signature in presence of two witnesses.; Y

JULES DHARVENG. TWitnesses:

LEONARD LEVA,

GEORGES VAN DER HAEYHEN.

Copies of this patent may be obtained for Vfive cents each, by addressing the Commissioner of Patents, Washington, D. C. v Y I v 

